An adult male chimpanzee has a head and body length of
30 to 36 inches and weighs up to 200 pounds. Females are
slightly smaller, being 28 to 38 inches long and weighing
up to 180 pounds. Overall height ranges from 3 to 5.5
feet, and the arm spread is 50% greater than the height.

Most of the body is covered with long, coarse black or
brown hair, but the face, ears, fingers and toes are
bare. As with humans, baldness is quite common among
mature chimpanzees, except that females tend to
experience it worse than males.

Chimpanzees have hands that can grip firmly, thanks to
an opposable thumb.

Distribution and Habitat

Chimpanzees live in the tropical rain forests of
western and central equatorial Africa. They are at home
in the trees, but often come down to the ground to search
for food.

Social Habits

Chimpanzees live in groups numbering from 15 to 140
individuals. The size of a group will increase as
chimpanzees gather at a source of plentiful food, and
will decrease as that source depletes, and individuals
move between groups frequently. The only constant unit of
social life is a mother with her young. She may have two
or three of different ages with her at any time because
they stay with her for several years.

Within a party, the males are arranged in a social
order, based primarily on age.

Chimpanzees are very "touchy-feely," often
kissing and/or "shaking hands" when they meet.
They also communicate with each other using a wide range
of facial expressions and vocalizations.

Reproduction

There is no regular breeding season, but females only
mate during heat, which lasts two to three weeks and
occurs every four to six weeks. During this time females
are quite promiscuous and will mate with any willing
male.

A single baby -- twins are rare -- is born after about
230 days. The quality of baby care shown by female
chimpanzees varies considerably -- from overly attentive
and protective to neglectful. In general, however, the
standard of care and education for chimpanzee young is
among the highest in the animal kingdom. In addition,
chimpanzee babies are among the most obedient children in
the animal kingdom, although juvenile delinquency is not
unheard of.

An infant can sit up at about 5 months and stand with
support at 6 months. It will be totally dependent upon
its mother until reaching about 2 years of age, and will
remain with her until about 3 years old. Sexual maturity
is reached between 7 and 10 years of age.

Feeding Habits

Chimpanzees spend up to 7 hours a day feeding, and
will investigate virtually any source likely to produce
food. Crevices in logs are searched for insects and nests
are robbed of eggs and chicks, but their usual food
consists of fruits, leaves and roots. Ripening fruit
crops are a special attraction to them and bands of
chimpanzees have been known to do considerable damage to
plantations before the ripened fruit can be harvested.

While 90-95% of the chimp's diet consists of plant
matter and insects, it is not at all unusual for an
individual chimpanzee to hunt down, kill, and eat small
monkeys, pigs, or even antelope.

Intelligence/Tool Use

The chimpanzee is one of the very few animals known to
make and use tools in the wild. Twigs and vines are
stripped of leaves and then used to "fish" for
termites. A stick may be used to enlarge the hole in an
ant hill. Leaves are chewed to make them more absorbent
so that they can be used to dip for water in holes in
trees. And, every night, each chimp constructs a nest of
vegetation in which to sleep. What makes tool use among
chimpanzees even more remarkable is the fact that
individual chimpanzees have been seen showing other
individuals how to make and use implements, and that the
quality of tool-making within a family group may actually
improve over the course of a few generations.

A chimpanzee demonstrates concept formation by
matching the peg shape with the correct hole.

In a classic experiment a chimpanzee was faced
with the challenge of getting to a bunch of bananas
hanging from the ceiling. With little hesitation, the
chimp stacked the three wooden crates that the observer
had "conveniently left behind," climbed to the
top of the stack, and got his "prize."

Chimpanzees have also been observed using medicinal
plants to treat themselves and others for illness and
injury.

Individual chimpanzees can recognize themselves in a
mirror -- as opposed to seeing the reflection as another
animal.